1. Field of the Invention
The present invention relates to an image forming apparatus, and a method of controlling the same, and, more particularly, to an image forming apparatus and a control method thereof, in which electrical connection between a developing unit and the main body of the apparatus can be made less susceptible vibration, contamination, etc.
2. Description of the Related Art
Image forming apparatuses are devised to form an image on a printing medium. Examples of image forming apparatuses may include, e.g., printers, copiers, facsimiles, and so-called multi-functional devices that combine some of the functionalities of the aforementioned.
Of the variety of image forming apparatuses, in an electro-photographic image forming apparatus as a kind of image forming apparatuses, light is irradiated to a photosensitive member charged with a predetermined electric potential so as to form an electrostatic latent image on a surface of the photosensitive member, and developer is fed to the electrostatic latent image, forming a visible image. The visible image, formed on the photosensitive member, is transferred to a printing medium directly or indirectly by way of an intermediate transfer member. The image transferred to the printing medium is fixed to the printing medium via a fusing process.
In the above-described printing operation, a developing device included in the image forming apparatus feeds developer to the photosensitive member, to form a visible image on the surface of the photosensitive member. Generally, the developing device takes the form of a cartridge in which a developer reservoir, a charger, a developing member, a cleaning member, etc. are integrated to a single unit. The developing device may be detachably mounted in a body of the image forming apparatus.
The developing device has a limited lifespan and must be replaced or replenished. To replace or replenish the developing device at an appropriate time for effective management of the image forming apparatus, it may be necessary for the user to know a variety of information about the developing device.
The developing device may be provided with a memory unit, which stores a variety of information required for management of the developing device. The memory unit may store information including a residual amount of developer and the remaining lifespan of constituent elements.
The memory unit is provided at one side thereof with developing device terminals, and body terminals corresponding to the developing device terminals are provided at the body of the image forming apparatus. Once the developing device is mounted to the image forming apparatus, the developing device terminals and body terminals come into contact with one another, achieving electrical connection therebetween. In a state wherein the developing device is electrically connected to the body, the image forming apparatus is able to recognize the information stored in the memory unit and display it to a user, or performs data transmission/reception to update the information stored in the memory unit by performing desired calculations using the recognized information and transmitting information relating to the results of the calculations to the memory unit.
To initiate a printing operation, the image forming apparatus typically undergoes a warm-up process to test the operational status of respective constituent elements including a drive motor. The warm-up process includes data transmission/reception via the memory unit. However, due to vibration caused during operation of the drive motor, etc., there is a risk of poor contact between the developing device terminals and the body terminals. To avoid malfunctions, thus the data transmission/reception to and from the memory unit is performed after the test operation of the drive motor, etc. is finished and the vibration has adequately subsided.
Conventionally, since time required for data transmission/reception on a per developing device basis can be up to about 2 seconds, an image forming apparatus including four developing devices may take up about 8 seconds for data transmission/reception alone. The time required for data transmission/reception causes an increase of First Page Output Time (FPOT) as a criterion to evaluate performance of the image forming apparatus.
To improve general printing performance of the image forming apparatus, and to reduce the FPOT, it is necessary to assure effective data transmission/reception between the developing device and the body of the image forming apparatus.
However, in conventional image forming apparatuses, the developing device terminal is merely embodied as a rigid gold-plated plane while, the body terminal that makes contact with the developing device terminal has a rigid convexly arched distal end. With this configuration, the developing device terminal and body terminal are electrically connected to each other through a single point of contact.
A drive device, e.g., a motor, is provided in the image forming apparatus, e.g., to move a printing medium for image formation or the like. Vibration occurs during operation of the drive device, and may temporarily interrupt the point contact between the developing device terminal and the body terminal, causing temporary open-circuiting of the electrical connection. Consequently, data transmission between the memory unit and the body is interrupted, resulting in malfunction of the image forming apparatus.
Further, during the use of the image forming apparatus, a developer leak may cause developer to be accumulated at the point contact region between the developing device terminal and the body terminal, resulting in a poor electrical connection.
To avoid the above-described problems, conventional image forming apparatuses stop the data transmission between the memory unit and the body during operation of the drive device. However, unfortunately, this adds the transmission stoppage time to the total printing time and consequently, increases the printing time and the FPOT, causing consumer dissatisfaction.